• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.541-547
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• 2007

게임 문화는 오프라인에서 온라인으로 중심축이 급격하게 바뀌었다. 급격한 변화는 온라인 게임의 발전 불렀지만 게임 문화의 획일화를 불러 오프라인 게임 문화를 잠식하였다. 그러나 보드게임 활발한 보급은 사람들에게 과거의 추억과 사람사이의 유대감을 다시금 불러일으켰다. 그러나 지식의 부족으로 한정된 보드게임만 즐기게 되고 또한 구매하여 즐기기에는 경제적 부담이 컸기 때문에 인기가 많이 하락하고 있다. 본 논문은 이 문제를 해결하고 오프라인 게임의 장점을 살리기 위해 우리가 개발한 AR-Table System을 제안했다. 이 시스템은 오프라인 게임과 온라인 게임의 장점을 융합하고 단점을 보완하고 증강현실을 사용하여 새로운 게임 개발 환경을 제공한다. 이 시스템은 Main Table System과 Personal Display Device로 구성되어 있고, 물리적 마커를 응용한 디지털 마커를 개발하였다. 이 시스템을 설명하기 위해 보드게임 Geister를 AR Geister로 개발하였다.

• Electronics and Telecommunications Trends
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• v.17 no.5 s.77
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• pp.15-25
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• 2002

사용자 요구의 다양화와 그에 따른 트래픽 증가 등 현재의 IMT-2000 기반에서 수용할 수 없는 보다 복잡한 이동 멀티미디어 환경이 도래하고 있다. 이러한 이동 멀티미디어 서비스를 원활히 제공하기 위해 ITU-R을 중심으로 한 전세계 이동통신 업계는 이미 4G 시스템 규격 및 개발에 상당한 진전을 보이고 있다. 이에 따라 ETRI도 지난 2002년 1월부터 4세대 이동통신 초고속 패킷 무선전송 기술 연구 개발에 착수하였다. 이 연구 개발은 크게 전송 시스템과 네트워크 분야로 나뉘어지며, 전송 시스템은 다시 low-tier 서비스를 위한 HMI 시스템과 high-tier 서비스를 위한 HMM 시스템을 두 축으로 하여 진행되고 있다. 본 고에서는 HMM 시스템의 연구 개발 계획, 전개 방향 및 목표 등을 간략하게 소개하고자 한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.429-432
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• 2000

본 논문은 급변하는 정보통신 기술의 효율적 개발을 위한 진단적 정보의 제공을 목적으로 하고 있다. 즉 기술개발 전략을 제언하기 위한 선결작업으로써, 기술개발의 대상에 대한 직접적 분석과 전략에 대한 시사점을 제공하려 함이다. 따라서 본 논문에서는 기술의 유형 구분을 위한 양 설명축을 설정하고, 이에 따라서 기술의 유형을 구분하게 된다. 그 후 이상의 그룹 설정에 대한 타당성 검증을 위해 T-test 를 실시하고, 이 타당성을 바탕으로 판별분석을 실시하여, 기술유형의 구분을 위한 판별식을 도출하였다. 이 판별식을 통해 기업입장에서는 기술개발을 위한 기술의 효과적인 분석이 가능할 것이다.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.9-15
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• 2004

In this paper, a HILS(Hardware-In-the-Loop-Simulation) System designed for an unmanned airship, which is under development by KARI, is introduced. A HILS system is essential to validate flight control systems on the ground. The HILS system consists of several systems: a virtual ADT(airborne data terminal) system, a virtual payload system, a virtual airship system, and a status display system. Also, a 3-axis motion table and an inertial navigation sensor are included. The reliability of the flight control computer has been validated by HILS tests.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.623-630
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• 2007

Grouting materials are used for the unification of superstructural and substructural body like bridge seat (shoe) or machinery pedestal and e.t.c by filling their intercalary voids. Accordingly, grouting materials have been developed and used mainly with products of high strength because those materials are constructed specially in a part receiving large or impact load. In this situation, the structural body constructed by grouting materials with high stiffness-centered (caused by high strength) products is apt to cause brittle failure when receiving over a limit stress and to cause cracks according to cumulative fatigue by continuous and cyclic load. In addition, grouting materials are apt to cause cracks by using too much rapid hardening agents that give rise to high heat of hydration to maintain high strength at early age. In this study, to overcome these problems, cement type grouting materials including powder of waste tire and resin as elastic materials which aim to be more stable construction and to be improvement of mother-body's unification are developed and endowed with properties of high toughness and high durability add to existing properties of high flowability, non-shrinkage and high strength. Besides, this study contribute to of for green construction materials for being possible recycling industrial waste like waste tire and flyash. On the whole, seven type mixing conditions are tested and investigated to choose the best mixing condition.

• Journal of Energy Engineering
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• v.2 no.3
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• pp.258-267
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• 1993

A mathematical model has been developed to describe heat transfer phenomena in a PCM (phase change material) module for development of an energy recovery system. The PCM module, melting point of which is around 1673 K, consists of silicon(96.8%), aluminium(2.7%) and marginal amounts of impurities such as Ca, Fe and Ti. The module is covered by a capsule that consists of SiC(58%) and graphite(42%). Physical properties that are required for model predictions were cited from the references. The apparent capacity method and the postiterative method wert used in the mathematical model to describe the phase changing mechanism. Temperature and velocity of fluid are the major variables in the model calculation. For the gas temperature of 1773 K that simulates real operating conditions, the prediction shows that PCM is rapidly melted to axial direction. However, for the gas temperature of 3000 K that is higher than the real conditions, PCM is melted rapidly to the radial direction. The gas velocity has no influence on the melting phenomena of the PCM except when the gas velocity is relatively low. At the low gas velocity asymmetry of the temperature profiles in PCM is obtained.

• Journal of the Korean association of regional geographers
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• v.23 no.1
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• pp.136-150
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• 2017

This study analyzed the spatial change of urban green spaces in Daegu from 1989 to 2009 using cell based spatial metrics. To do so, the conversion process of land covers during the past 20 years was explored using a land cover change detection matrix. The synoptic analysis with a moving window sampling strategy was conducted to quantify cell based spatial metrics related to size, shape, cohesion, and diversity and to explain the spatial change at the local level. Difference maps were then generated by subtracting the 1989 maps of spatial metrics from the 1998 maps and the 1998 maps from the 2009 maps. The gradient analysis was performed to identify the directional change of spatial metrics along an urban development axis in Daegu. The results from this study show that urban green spaces in Daegu during the past 20 years have been gradually fragmented around the new town housing development districts such as Dalseong-gun, Seongseo, and Ansim. Forests were most prominently fragmented in the Hwawon area while most rapidly in the Chilgok area. Grasslands were largely fragmented in many areas due to the decrease in size and cohesion indices and most fragmented in the Ansim area. The spatial pattern of the decreased and fragmented urban green spaces identified by this study can be used as a base data for establishing the environment-friendly urban development strategy in Daegu.

• The Korean Journal of Nuclear Medicine
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• v.39 no.1
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• pp.49-56
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• 2005

Purpose: Dedicated animal PET is useful equipment for the study of new PET tracer. recently, microPET R4 was installed in the Korea institute of radiology and medical science. In this study, we measured the characteristics of scanner. Materials and methods: Resolution was measured using a line source (F-18:65 ${\mu}Ci$, inner diameter: 0.5 mm). The line source was put in the axial direction and was moved from the center of field of view to outside with 1 mm interval. PET images were reconstructed using a filtered back-protection and ordered subset expectation maximization. line source (16.5 ${\mu}Ci$, 78 mm) was put on the tenter of axial direction to measure the sensitivity when the deadtime was under 1%. Images were acquired during 4 minutes respectively from center to 39 mm outward. Delayed count was subtracted from total count and then decay was corrected for the calculation of sensitivity. Noise equivalent count ratio and scatter fraction were calculated using cylindrical phantom. Results: Spatial resolution of reconstructed image using filtered back-projection was 1.86 mm(radial), 1.95 mm(tangential), 1.95 mm(axial) in the tenter of field of view, and 2.54 mm, 2.8 mm, 1.61 mm in 2 cm away from the center respectively. Sensitivity was 2.36% at the center of transaxial field of view. Scatter fraction was 20%. Maximal noise equivalent count ratio was 66.4 kcps at 242 kBq/mL. Small animal images were acquired for confirmation of performance. Conclusion: Performance characteristics of microPET R4 were similar with reported value. So this will be a useful tool for small animal imaging.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.13-24
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• 2009

This study developed a high strength and performance concrete pavement material with low shrinkage and reflection of sunlight. Based on the literature review, a new mix-design of applying flash ash to improve the strength and performance of the concrete as well as to reduce the dry shrinkage is suggested. In addition, adding black pigment to reduce the reflection and technique of applying OAG (Optimized Aggregate Gradation) is also included. The result of the laboratory experiment indicates that the brightness and the reflection, which depends on the ratio of black pigment addition, did not deviate from the normal range. When OAG is considered for the mix-design, the strength and performance of the concrete improved greatly. In addition, the mix-design using fly ash reduced the dry shrinkage of concrete and improved the resistance to the permeation of chloride ion. Furthermore, the mix-design, which uses fly ash (25% replacement) and black pigment (3% addition) with the application of OAG, is found to be the most effective mix to reduce the shrinkage and reflection as well as improving the strength and performance of the concrete. The result of an economic analysis indicates that the initial construction cost of this proposed mix is more expensive than that of normal concrete pavement material. However, it can be more economic in the long run because the normal concrete pavement material is likely to cost more due to higher probability of maintenance and repair and higher social cost due to traffic accident, etc.

• Journal of Nutrition and Health
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• v.56 no.6
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• pp.602-614
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• 2023

Purpose: The balance between synthesis and degradation of proteins plays a critical role in the maintenance of skeletal muscle mass. Mitochondrial dysfunction has been closely associated with skeletal muscle atrophy caused by aging, cancer, and chemotherapy. Polygalacin D is a saponin derivative isolated from Platycodon grandiflorum (Jacq.) A. DC. This study aimed to investigate the effects of polygalacin D on myoblast differentiation and muscle atrophy in association with mitochondrial function in in vitro and in zebrafish models in vivo. Methods: C2C12 myoblasts were cultured in differentiation media containing different concentrations of polygalacin D, followed by the immunostaining of the myotubes with myosin heavy chain (MHC). The mRNA expression of markers related to myogenesis, muscle atrophy, and mitochondrial function was determined by real-time quantitative reverse transcription polymerase chain reaction. Wild type AB^* zebrafish (Danio rerio) embryos were treated with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) with or without polygalacin D, and immunostained to detect slow and fast types of muscle fibers. The Tg(Xla.Eef1a1:mitoEGFP) zebrafish expressing mitochondria-targeted green fluorescent protein was used to monitor mitochondrial morphology. Results: The exposure of C2C12 myotubes to 0.1 ng/mL of polygalacin D increased the formation of MHC-positive multinucleated myotubes (≥ 8 nuclei) compared with the control. Polygalacin D significantly increased the expression of MHC isoforms (Myh1, Myh2, Myh4, and Myh7) involved in myoblast differentiation while it decreased the expression of atrophic markers including muscle RING-finger protein-1 (MuRF1), mothers against decapentaplegic homolog (Smad)2, and Smad3. In addition, polygalacin D promoted peroxisome proliferator-activated receptor-gamma coactivator (Pgc1α) expression and reduced the level of mitochondrial fission regulators such as dynamin-1-like protein (Drp1) and mitochondrial fission 1 (Fis1). In a zebrafish model of FOLFIRI-induced muscle atrophy, polygalacin D improved not only mitochondrial dysfunction but also slow and fast muscle fiber atrophy. Conclusion: These results demonstrated that polygalacin D promotes myogenesis and alleviates chemotherapy-induced muscle atrophy by improving mitochondrial function. Thus, polygalacin D could be useful as nutrition support to prevent and ameliorate muscle wasting and weakness.